Submarine signaling



July 24, 192s. 1,678,184

J. J, GILBERT SUBMARINE SIGNALING Filed June, 30, 1925 2 Sheets-Sheet l July 24, 192s. 4 1,618,184

J. J. GILBERT SUBMARINE SIGNALING Film1 June so, 192:5 2 sheets-sheet 2 ATTENUATIDN 0F ELKIRIC'FIELDNTENSITY nv .sen wnrn AT vAmaua umn: as mtovgucles 1 1 l0 zo, 5o 40 5 6o 10 00 9o lo 500 frequency v coNnNuousLY www sueMAmur. Qms /C/ CHARACTERlsTlc IMPEDANCF.

400 fuman nce 300- n E .C O 20a#- Reacance Patented July 24, 1928.

UNITED SteiltS'v1Marzoemacs. 1

Jenn a. GILBERT, or, roar Wasi-Imation, New YORK, AssIeNon 'ro WESTERN ntnornrc COMPANY, INCORPORATED, OF NEW YORK.` N. Y., CORPORATION OF NEW YOIBK.`

` sUBMAnrN'E siGNALING.

Application led June 30,k

` The invention relates to submarine sigmaling'v and has for an object to reduceextraneous interfering electric Waves picked up by a submarine cable in order that the limit upon signal legibilityset by this vinterference will. be diminished and the speed of operation increased, v p.

This Objectis accomplished by using asea earth termination which is immersed/at a depth which is suliiciently great so thatthe effect otthe disturbing electric Wavesbeyond that depth is negligible, advantage being taken of the fact that for a disturbance of a given frequency, there is a depth of Water in ivhich a cable vvill pick up only a negligible amount of disturbance. turbing` electric Waves at lesser depths is made negligible by the sea earth connection by reason of the balanced relation of the main cable and that leading to the sea earthtermination with respect to the receiver. These-two cables have similar electrical characteristics sothat interference picked up by them is of the same amount in each and in opposite directionwith respect to the receiver.

Another object of the invention is to pro-v vide a terminating impedance which simple inform and of such a construction that it may be of the saineA configuration as the submarine cable, in order that itV may be located adjacent the sea earth termination.

Referring to the drawingalg. l isv a1 cross f section of the ocean over the route to be traversed by the cable;y Fig. 2 is an enlarged View of the Western end of the cable and the y ocean route. Fig. 3 is across section of a cable providing a terminating impedance and a sea earth termination.' Fig.y '4; illustrates how the high-resistancervvires, comprising the terminating impedance, may be soldered yto the cable and to the terminal.

The curves in Fig-5 illustrate the attenua-` tion of disturbinglelectiic field intensitiesvof differentfrequencies by sea Waterfat various depths.' The curves in Fig. 6 illustratethe variation in resistanceandreactance,,of continuously loaded submarine 'cable with frequency. 7 illustrates a loaded cable, and Fig. 8 illustrates a Vcable providedk with separate sea earth' terminations fortransmitting and receiving.` i y Referring in detail to the drawings, it is seen from the curves inflig. 5 that the at The ,effect Iof dis- 1923. Serial` No. 648,690.

tenuationof an extraneous electric disturbanceincreases for a given frequency as the 4depth of immersion increases. Advantage is` root of', the frequency, assuming that disturban'ces of all frequencies have the same amplitude at the surfaceof thewater.

` Vhereas, according to prior practice, it hasbeen the custom to havethe sea earth termination only five miles or so from the shore and immersed in water ofl about fifty feet in deptlnaccording to the `present invention, it

isproposedto immerseithe sea earth termination to a depth of approximately five hundredy feet and this Wilhin general, re-

qui're a much longer'section of sea earth cable 1 than has been used before, and inthe case of a cable between New York andthe Azores,

for instance, it Will be advisable to use a sea earth cable about one hundred miles in length at the Western end. At the eastern end a inuchshorter length will be required. A cross section of-an ocean cable route is illustrated in Figsl and2. From the above.

considerations, it Will be apparent thatat the Western`end, practically all the disturbances of. frequencies which are passed' by theref ceivmg apparatus used on such a cable, that is tfrequencies of about oney hundred cycles persecond, will be picked up in the length TC, Fig. 1, thelpartcontributed'by CD kbe-r ing negligible on account of the great depth.

In order to avoid difficulties attendant from laying heavy cablein greaty depths of Water, the sea earth terminationcan be located at the, point B,`F ig. 2, where the bottom begins `to kfall oitl towards very great depths. The

sys

. torl, provided with a/Wrapping-Q kot ironi nichel alloy composed prcterablyof'r" d1/2% due to the tact that signalsas received over a submarine cable contain a large. proportion;

et low frequency components which mustl be reduced in amplitude by correcting `Also it vis to und that LAforintelligible signals,

trequencies which are higher than ak certainA multiple ot the dot 'frequency aref not rel"y quired, so that low pass4 filters canbev pro,- vided in the receiving network to remove disquency ofthe received signals... p n

A preferred term -ot' mam cable, as illus# trated in F 1g. comprisesa copper 'concluenickel 1 and 211/%k iron,` asl described and claimedin patentjto Ilillmen,jl\lo.21,586,887,- June 1,1926. Theadvantage orl this l`oad-I ing material is `that its permeabilityatsmall magnetizing forces ot the order ot 0.01' to O.10fgaussis trom ten totwenty times that ot iron, that is, trom 3,000 to@6,000. llith a loaded cablefot this sort, it has been-foundryl as illustrated ein Fig.6,that thefcharacter-f istie impedanceat the frequencies of 'interest` incablefworlr, is practically a constant' re` sistance with Yonlyra small.-r `1,acta.nce. It

can he seen from-these' curvesthatl tor tre,`

qucncies otthirty cycles and higheiga resist ance ot about 4:00 ohms will diiiier by on'lyfa inductanc'e and capacity, "respectively, of 'the' cable. f Preferably, this 4termin'a'tin'g'fin1ped- 2 ance is located adjacent-the ksea"earthder` minationA 'as ydescribefdand claimed"V in the patentj to Osbdrn'e, l 13 f '1921.

termination and foreonnectingtoit there-.

sistance which seri/es asthe terminating im-' pedance. 'Alength ot about seven hundred feet ot high' resistivity'lmaterial such as nichrome 3, madenpot seven strandso'f No,

Q8' gauge' 'wire is `joinedf'atflo'oth, ends-to stranded copper Wire 445 ot 'abo-utthe same are made by ,solderinglthe individual strands of the. copper 4-5 andtheresistancecyvires 3 in the mannerj shown in 'Fig.,4, the ysev*` eral Ajoints"beingdistributed ver a lengthV net-v works, Whi ch,Y arc cssent'iallyhigh pass filters:

, 15,390,580', yS(reptembe'r r The arran'genientilliistrated iii'lFigsf' 3 and i 4 'may be yused [for forming thef'seal earth et several feet so as to provide taper 6 7 yand 8e4) between" the conductors, and to strengthen the joint mechanically; The compositeY conductor is insulated with gutta perchaor the-like 10to about the same diameteras rtho-coreof the maincable, and over this is laid a thin brass or copper tape 11 which"turnishes mechanical strength and Which has-a .low resistance contact With the sea Water and yserves 'as the sea earth terminavtien. .The high` resistanceconductor 3 with itsterininals 4t and rv5 are soldered at the end.

4: to the sea earth cable' conductor shown in been.terminated,andis soldered at the other end,-tor instance, as 'shown' at 12, to the tape or equivalent conductor 11. It' desired a `protective metal cap 13 mayl be placed over rtheend ofthe tape 11iy The sea earth terminating network is thus I madeaV continuation of the corey of the sea earthcable=and-can be `served with# jute and armored as part ofthat core.` rAlljoints of ditterentinetals are WellprOteCted from the sear` .Water so ythat galvanic electromotive torce'szare not set-anp.

l The ysea-earth,cable maybe either enclosed inthe same sheath as the main-cable or in grounded on the armor of the main cable.-

In-the pr.eceding,.it has been assumed that the ytwo cores,y i.e., the main and thev sea earth cable cores, are exactlyy alike so that they 'chave the same electrical parameters. Lackot such equalit'yat any point Will give rise to interference, the magnitude'of' which can be determined. by the method outlined previously In' order that they arrangement oty seaearth termination that has been -de'- scribed shall be tully effective, it is necessary that the parameters otthe t\vocoresshall`be prescribed percentage.V l y By." employing a sea eartl'i' termination of lthe type, that has ,been described, the trans mission eiiiciency of -th'ecable'will be deik resistanceY andto thetaet thatthe tvvincore cable,}.1n some casesone hundred inlles or ationV constant than; the single core. type' ot cablerff The advantage kot vthe arrangement is thatfinterlterenc'e' due ltoextraneous disturbancesis diminished t0y a `much; `greater extentfthanjthe transmis-.sion efficiency. Ine

order toiner'ease the etliciency of/the cablel system, th`e 4,sea earth cable can becutiloose from thesystem-atthe sendingfendand trans-y mission-can beeft'ected bv means' of direct l gronndfatythat pointy' It is possible, honkV diameteras the cable conductor., 'lhejointsy ever, th'atkthey local disturbances Will be ot suchlarge magnitude, that even `When transmittedoverythe entire cable,- they will cause l serious-interference.Withthe signal. Insuch ay casepit Would'be desirable to employl the Fig. A"I, on which the loading material 2 Ahascreased dueto the presence ot theL terminal' more in length`may Ahavefafhigher attenu` an independent :sheath and it mayy be.

lll() substantially eqn ill' all pointsy to Within f a y llUv arrangement shownin Fig. Sand according to Which a thirdcore 14 extends for a few miles from shore and isv grounded on the armor of themain cablel or on a copper or brass tape Wound around vthe core in the manner shown in Fig. 3. The high resistance sea earth termination illustrated in Figs, 3 ande, is used in the sea earth cable 16 illustrated in Fig. 8. The cable 16 gives veryeiiicient results when used for receiving purposes, and asvvitch 17 has been shown for connecting the main cable 15V in circuit with the receiving device 2O `and the cable 16. The cable 14 being of very loivresistance as compared to the ca'ble"16,is`prefer-k able for transmitting purposes and the sivitch 17 is, therefore, provided to connect the main cable 15in circuittvith cable 14, a condenser 18 and the usual transmitting apparatus 19 being then connected vvith these cables.

It is important to note that in the case ot non-loaded submarine cables the conditions are such that the method ust described is of relatively small advantage. The reason is that on short cables Where high signal Ispeeds are attained and disturbances of high frequency are of importance the `cable usually lies in suc-hshallow Water that there is no point at which the sea earth cable can be terminated, with theV insurance that the dis# turbance picked up on the remainder ofthe cablerwill be of negligible effect. The same line of reasoning applies to longer cables,

. Where the depth of lsubmersion is lilrely tok bcgreater. The frequencies involved in this case are so lovvy that disturbances penetrate to great depths and are picked up over the entirey cable. What is claimed is:

1. A terminating impedence for a loaded cable having a resistance equal to negligible, a sea earth termination, anda terminating impedance of substantially pure resistance connecting the sea terminal of said sea earth conductor to said sea earth termination, the terminating impedance serving to terminate the sea earth conductor in such an impedance, at a frequency in the neigh borhood of the dot frequency, to prevent reflections `at saidsea terminal atsaid fre-L quency.

"3. Themethod of attenuating disturbances i rpicked up by a submarine cable employing a. sea earth termination which comprises 1mmersing said sea earth termination to a depth of the order of tive hundred feet.

LA loaded submarine cable, a high resist-ance receiving circuitthereior, a low re# sistance` transmitting circuit therefor, and' means tor` alternately connecting said circuits to said cable.

5L In combination, a long, deep sea cable conductor, a return conductor of similar electrical characteristics extending adjacent said cable conductor from shore to a point at which the Water is of considerable depth andv unctionino' to balancean e ual length of the sea cable conductor a. terminatino impedance insulated trom the vsea having one terminal connected to the sea terminal of the tenuate disturbances propagated from the surface down to the "conductors to a small fraction oftheir surface'fmagnitude, said return conductor having a connection to earth in the vicinity of said point, and receiving apparatus connected to the two conductors att-heir adjacent shore terminals;

` 7. In combination, a long, deep sea cable conductor, a return conductor of similar electrical design extending adjacent said cable conductor from a shore terminal to a point at Which the depth of Water is suflicient to attenuate external disturbances, Within the range of the signaling. frequencies employed, to a small traction of their magnitude at the surface of the sea; a complemental impedance element connected to the return conductor at `its sea terminal and having impedance characteristics simulating those ot the main cable conductor viewed in the direction to sea at the same point, andv receiving apparatus connected ,to the tivo conductors at their adjacent shore terminals.

8. In combination, a loaded, long, deep sca cable conductor, a sea return conductor ofsimilar -design extending adjacent said cable yconductor from a short terminal to a point at sea, an insulated resistance element connected to the sea terminal of said sea return conductor at one terminal, the other terminal of said resistance element being connecte-d to earth, and receiving apparatus yconnected to thetwo conductors at their ad jacent shore terminals.

als

als

9.. The `cloinbin ation witha long high speed submarine cable, of ,reeeivin g and transmitting apparatus therefor at each terminahya.

sea. earth; terminationvat-feach terminal lo- .cated at a4 relatively` great depth and oon:4

neeted to the receiving apparatus at that terminal through af cable parallelingethe main cable and similar thereto,ineleetrieal eharaeteristirs, a. second sea earthy termination at eaoh terminal,-loeated at a lesser depth than ,said 'first mentioned sea earth iand,

connected to the transmitting apparatus at` that terminal through a relatively shorty length ot cable vparalleling the main hable,

e and switchingmeans `Iat veach yterminal, for.`

associating lthe. main cable valternately either with lsaid reeeivingor transmitting apparatus atl that terminah` f 10. yThe combination lwith 'tirstmentioned seaearthiand connected to the transmitting apparatus at that terminal throughy a relativelyshort length of kcable paralleling the main Cable, and ,suf'itehing vmeansat each ,terminal forl associating the main cable alternately either With said ref eeivingortransmitting apparatus at that terminal.

11.` Terminal apparatus for along, highl speed submarine cable eomprisingreoeiving a long,jhigh speed submarine eahle, oii lreceiving and and transmitting apparatusy having :separate sea )earthterminations connected thereto re-v speetively,U and at diierenttdistanees therefrom., y t e f l2. A' terminatingimpedanee. fora ysubmarinel oable,tsaid impedance being in the form of afeable and comprising a high resistanee con duetor, insulation` resistant toy y:sea Water surrounding" saidfyeonduetor, aI vmetallic sheath in Contact with thesea ,Watersurrounding-,said insulationand a metallie connection between; said-resistance eonduetor andsaidrmetallie.sheath,f i y y y 13. A loadedsubmariue Cableandnieans :for diminishing the eleet, otextraneous in! terfering eleetrie `Waves comprising iid-secondl conductor adja'en't. toI and ,'parallelingmthef conductor of the cable :extendingfrom ,ater-y ininalof theeable to apointat sea andterminating at the sea endinay l "in-inating im-A pedance consisting substantially Whollyof" pure resistanee., f n I Q14.-` Ailoaderlfsubmarilne eableanyd means for diminishing the efeetfof extraneous in-r terfering electric kWaves`.Comprising .a second conductor adjacent to and'paralleling the conductor of the cable extend!inglfromlav termina] of the vcable toga pointatsea andlterminating at the `seagend in a,terminating'impedance consistingy substantiallyiwholly yolf pure resistance,` ,said terminating impedance beinglocated at a point 4so. farremoved ykfromk the shore `end of the cable that the remainder of. thefeable Will` be in. Water of 'such1 depth:

ithahtthel eleet of said lezvdraneous Waves Will be negligible.

In 4Witness Wlyiefre off` I `hereunto' subscribev n my name thisQthday 'ofJune Af. DL, 1928,.

i JOHN J.l einnier; j 

